Echinopericlimenes, Marin, Ivan & Chan, Tin-Yam, 2014

Marin, Ivan & Chan, Tin-Yam, 2014, Deep water echinoid-associated pontoniine shrimp “ Periclimenes hertwigi Balss, 1913 ” species group (Crustacea: Decapoda: Caridea: Palaemonidae): species review, description of a new genus and species from Philippines, Zootaxa 3835 (3), pp. 301-324 : 302-303

Echinopericlimenes gen. nov.

Type species. Periclimenes hertwigi Balss, 1913 ; by the present designation.

Species included. Periclimenes hertwigi Balss, 1913 , Periclimenes dentidactylus Bruce, 1984 , Periclimenes calcaratus Chace & Bruce, 1993 and Echinopericlimenes aurorae sp. nov.

Etymology. The name refers to the association of representatives of the new genus with sea urchins (Echinodermata: Echinoidea) and the previous reference to the genus Periclimenes Costa, 1844 s . l.

Diagnosis. Large and medium-sized pontoniine shrimps with subcylindrical body. Carapace smooth, not pitted, swollen, with antennal and hepatic teeth; antennal tooth small, situated just under orbital angle; hepatic tooth larger than antennal, situated behind and lower than antennal, with tip overreaching pterygostomial margin of carapace. Rostrum long, slender, compressed, directed downward, reaching distal margin of antennular peduncle or sometimes overreaching it; proximal lateral lamina feebly developed, armed with well developed dorsal teeth, the most proximal dorsal tooth sometimes situated slightly posterior the level of orbit; ventral margin feebly developed, with 1–2 teeth situated at the distal third of dorsal carina of carapace. Pterygostomial angle rounded. Abdominal somites smooth; pleurae of abdominal somites I–V rounded. Telson about twice longer than proximal width, narrowing distally, with 2 pairs of small dorsal submarginal spines, distal margin armed with 3 pairs of spines. Eyes large, with large oval cornea, about 0.1–0.2 of pcl, and stout conical eyestalk. Antennula well developed, compressed; basicerite with distolateral angle armed with large tooth and rounded medial projection, with small ventromedial tooth. Antenna normal, basicerite armed with large lateral tooth overreaching segment; carpocerite long and slender; scaphocerite well developed, wide, bearing sharp distolateral tooth slightly overreaching blade. Mandible robust, without palp; incisor process well developed, with 3–4 terminal teeth; molar process robust, with stout, sharp distal teeth. Maxillula normal, palp well developed, bearing large triangular pointed dorsal lobe. Maxilla with simple palp and slender bilobed dorsal endite; scaphognathite well developed. Maxilliped I with well developed exopod with normal caridean lobe; with large, ear-shaped epipod. Maxilliped II normal, with well developed exopod; without podobranch. Maxilliped III robust, exopod well developed, slightly overreaching antepenultimate segment. Pereiopod I slender, with simple fingers, with entire cutting margins and simple tips. Pereiopods II (chelipeds) similar in shape and slightly unequal in size; major pereiopod II with slender merus and ischium armed with small teeth along ventral margin, dorsally smooth; carpus small, triangular in shape, slightly overlapping carpo-propodal articulation, with straight margins; propodus cylindrical, covered with small tubercles, fingers stout with large triangular tooth proximally, cutting edge slightly convex distally, tip simple and curved; minor pereiopod II similar to major one but smaller. Pereiopod III relatively slender, with unarmed proximal segments; carpus and propodus slender; propodus with straight lateral margins bearing 5–6 slender spines along ventral margin and several slender spines at the distoventral angle, with tuft of stout flattened setae at dactylo-propodal articulation; dactylus slender, about 3 times as long as wide, with straight ventral margin, distoventral margin serrated or bearing several strong teeth; unguis small and curved, serrated ventroproximally, unarmed distoventrally. Uropods normal, well developed; distolateral angle of exopod sharply produced, with movable spine.

Differential diagnosis. The new genus possesses some features unique within the subfamily: 1) large hemispherical cornea of eyes and smaller conical eyestalk; 2) large hepatic tooth extending far beyond pterygostomial margin of carapace; 3) highly specific distoventral margin of dactyli of ambulatory pereiopods (pereiopods III–V) armed with several large teeth or finely serrated. The shape of mouthparts (i.e. the presence and shape of palps of maxillula and maxilla) and fingers of pereiopods II suggest that the new genus is closely related to “ Periclimenes alcocki Kemp, 1922 ” species group (Bruce, 2005, 2006, Li et al., 2008). All known species of the new genus are probably similar in ecology associated with deep water venomous sea urchins of the family Echinothuriidae (Echinodermata: Echinoidea).